WASHINGTON — President Barack Obama’s budget would generate unsustainably large deficits averaging almost $1 trillion a year over the next decade, according to new estimates released Friday.

The new Congressional Budget Office figures predict Obama’s budget will produce $9.3 trillion worth of red ink over 2010-2019. That’s $2.3 trillion worse than the administration predicted in its budget just last month.

Worst of all, CBO says the deficit under Obama’s policies would never go below 4 percent of the size of the economy, figures that economists agree are unsustainable. By the end of the decade, the deficit would exceed 5 percent of gross domestic product, a dangerously high level.The latest figures throw a major monkey wrench into efforts to enact Obama’s budget, which promises universal health care for all and higher spending for domestic programs like education and research into renewable energy.

The dismal deficit figures, if they prove to be accurate, inevitably raise the prospect that Obama and his allies controlling Congress would have to consider raising taxes after the recession ends or else pare back his agenda.

White House budget chief Peter Orszag said that CBO’s long-range economic projections are more pessimistic than those of the White House, private economists and the Federal Reserve and that he remained confident that Obama’s budget, if enacted, would produce smaller deficits.

Even so, Orszag acknowledged that if the CBO projections prove accurate, Obama’s budget would produce deficits that could not be sustained.

“Deficits in the, let’s say, 5 percent of GDP range would lead to rising debt-to-GDP ratios that would ultimately not be sustainable,” Orszag told reporters.

Deficits so big put upward pressure on interest rates as the government offers more attractive interest rates to attract borrowers.

“I think deficits of 5 percent (of GDP) are unsupportable,” said economist Mark Zandi, chief economist at Moody’s Economy.com. “It will lead to higher interest rates to the point where it will force policymakers to make changes.”

Republicans immediately piled on.

“This report should serve as the wake-up call this Administration needs,” said House Minority Leader John Boehner, R-Ohio. “We simply cannot continue to mortgage our children and grandchildren’s future to pay for bigger and more costly government.”

But Obama insisted on Friday that his agenda is still on track.

“What we will not cut are investments that will lead to real growth and prosperity over the long term,” Obama said. “That’s why our budget makes a historic commitment to comprehensive health care reform. That’s why it enhances America’s competitiveness by reducing our dependence on foreign oil and building a clean energy economy.”